Field of the Invention: The present invention is in the field of coating compositions, more particularly to high solids coating compositions.
Brief Description of the Prior Art: Governments in many countries including the United States are requiring the coatings industry to develop coating compositions which emit low amounts of organic material upon curing. Formerly, coating compositions were formulated with high molecular weight organic polymers. Although these polymers provided coatings with good physical and chemical properties, they were viscous and required considerable thinning with volatile organic solvents for good handling and application properties. Upon curing, these solvents would volatilize being emitted to the atmosphere where they posed environmental health problems.
In response to governmental pressure to solve these problems, the coatings industry has developed water-based and high solids organic coating compositions. The high solids compositions are made with low molecular weight organic polymers in combination with curing agents. These compositions are fluid and do not require much thinning with volatile organic solvents. The coatings can be applied at relatively high percentage resin solids which minimizes the amount of volatile organic solvent which is emitted to the atmosphere during curing.
One method of formulating high solids coating compositions is to use so-called "reactive diluents" which are capable of thinning the coating composition yet are reactive with a curing agent so as to become part of the cured film. An example of a reactive diluent is the reaction product of a glycidyl ester such as the glycidyl ester of Versatic acid with a hydroxy and/or carboxy functional compound as described in U.S. Pat. No. 4,314,918 to Birkmeyer et al.